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vol. 8 num. 4 lang. pthttp://www.scielo.br/img/en/fbpelogp.gifhttp://www.scielo.br
Variables impacting poultry meat quality from production to pre-slaughter: a review]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400001&lng=pt&nrm=iso&tlng=pt
Poultry meat quality has been widely studied, and has become a growing demand of the international market. Parameters that affect meat quality are complex, and occur throughout the production chain. The constant concern with meat quality by the exporting sectors is a response to consumers' demands, and is achieved by increasing efficiency, and investments in personnel training on quality. Understanding where critical points are in the poultry meat production chain, and investing in solving critical problems may lead to better control and management, and consequent reduction of losses. Production and management practices, from farm to processing plant, play an important role in meat quality, and the use of technologies to reduce risk factors throughout the production chain will allow the production of better quality poultry meat not only for exports, but also for the domestic market. This review describes the main factors that influence poultry meat quality in the production chain.Beak-trimming methods and their effect on the performance of japanese quail pullets (Coturnix japonica)]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400002&lng=pt&nrm=iso&tlng=pt
This study aimed at verifying if beak-trimming methods in Japanese quail pullets could optimize production by decreasing stress caused by cannibalism. A total number of 816 day-old Japanese quails was distributed in a completely randomized experimental design in a 2 x 3 factorial arrangement, with two beak-trimming ages (14 and 21 days of age) and three beak-trimming sizes (not trimmed, 1/3 trimmed, or 1/2 trimmed), and 4 replicates of 34 birds per replicate. Birds were submitted to the same management and feeding conditions. Weight gain, feed intake, feed conversion ratio, and mortality were evaluated. There was no significant effect of age at beak trimming on the evaluated parameters (P>0.05), as well as no significant interaction between age at beak trimming, and beak-trimming method. There was a significant effect (P<0.01) of trimming size on performance, with the best performance observed in birds not submitted to beak trimming or had 1/2 of the beak trimmed. When the beak was more aggressively trimmed (1/2), parameters were worse. According to the obtained results, it is recommended to trim 1/3 of the beaks, which can be performed either at 14 or 21 days of age.Histomorphology of bursa of Fabricius: effects of stock densities on commercial broilers]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400003&lng=pt&nrm=iso&tlng=pt
During the past few years, there has been considerable interest on the effects of stocking density on broiler behavior and immunity. Stress may cause immunodeficiency by affecting cell and humoral responses, as well as body weight decrease, and foot-pad dermatitis. The aim of this study was to study histomorphological changes of the bursa of Fabricius in broilers submitted to three different stocking densities (10, 15, and 20 birds/m²) from one to 42 days of age. Three birds from each group were sacrifieced on days 7 and 42. The bursa was collected, fixed, and processed for histomorphometric assessment using a Kontrom KS 400 image analyzer. Data were analyzed by Biostat 3.0 (Tukey Test). The results of average cortical area percentage in bursal follicles of 6-week-old birds were 45.12a (10 birds/m²), 30.43b (15 birds/m²), and 23.77b (20 birds/m²). Average body weight was 2.58a kg (10 birds/m²), 2.56a Kg (15 birds/m²), and 2.47b Kg (20 birds/m²), respectively. The percentage of foot-pad dermatitis in 6-week-old birds was 3.33a (10 birds/m²), 17.76b (15 birds/m²), and 49.17c (20 birds/m²). These differences were statistically significant at a P<0.05 level. Under these experimental conditions,, it was concluded that the best stocking density to produce broilers is between 10-15 birds per square meter.Evaluation of yeast cell wall on the performance of broiles fed diets with or without mycotoxins]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400004&lng=pt&nrm=iso&tlng=pt
This experiment aimed at evaluating the effects of the interactions between aflatoxin (500 or 250 ppb) and ochratoxin (500 or 250 ppb), and the possible benefits of adding yeast cell wall to prevent the effects of these mycotoxins in broiler chickens. Relative organ weight gain and live performance were evaluated at 21 and 42 days of age. Results indicated that at the levels of mycotoxins included in the experimental diets, ochratoxin reduced feed intake and body weight gain, and aflatoxin only affect feed intake of 21-day-old birds. No interaction was observed between aflatoxin and ochratoxin at the levels used in experimental study. Yeast cell wall did not significantly reduced the deleterious effects of ochratoxins. No significant differences were observed in relative organ weight gain. Yeast cell wall improved feed conversion ratio when birds were fed either contaminated or non-contaminated feeds.Different criteria for feed formulation based on digestible amino acids for broilers]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400005&lng=pt&nrm=iso&tlng=pt
An experiment was carried out to evaluate different criteria in feed formulation based on digestible amino acids for broilers during the grower phase. Diets were formulated according to the recommendations for digestible methionine, methionine + cysteine, lysine, and threonine. A total number of six hundred Cobb 500 male day-old chicks were distributed in a completely randomized experimental design, with three formulation criteria supplying the recommendations established by Baker & Chung (1992), Degussa (1997), and Rostagno et al. (2000), with 4 replicates of 50 birds each. No significant differences were observed for weight gain and feed intake. However, feed conversion ratio improved when birds were fed the diets containing the profiles recommended by Baker & Chung (1992) and Degussa (1997). No difference was observed in terms of leg, wings, back, and head yields. Broilers fed with the profile of Baker & Chung (1992) presented worst breast yield, whereas those fed the Degussa (1997) standard had better carcass yield.Influence of delayed placement and dietary lysine levels on small intestine morphometrics and performance of broilers]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400006&lng=pt&nrm=iso&tlng=pt
This experiment studied the influence of delayed placement (HI) and digestible lysine level (DL) on the morphometrics of the intestinal mucosa and on the performance of broilers. A total number of 1,705 Cobb 500 male chicks were used in a completely randomized experimental design in a factorial arrangement with four HI (12, 24, 36 and 48h), and two DL level in the starter diet (1.143 and 1.267%), with four replicates and 55 birds per experimental unit. The amino acids methionine-cystine, threonine, and tryptophan were balanced according to the ideal protein (IP) concept. Small intestine morphometrics was evaluated using histology slides of the duodenum and jejunum. There was no interaction between HI and DL levels for any of the studied parameters. The 1.143% level of DL promoted better performance results at 21 and 42 days of age, as well as higher duodenum and jejunum crypt depth, and duodenum villi height at 21 days of age. HI negatively influenced the morphometrics of the small intestine during the starter phase, and the performance of broilers up to 42 days of age. There was no effect of the treatments on yolk sac utilization or abdominal fat percentage. It was concluded that the use of 1.143% DL and HI of 12 hours promoted better development of the small intestine mucosa up to 21 days of age, and broiler performance at market age.Influence of glutamine and vitamin E on the performance and the immune responses of broiler chickens]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400007&lng=pt&nrm=iso&tlng=pt
This study aimed at evaluating the influence of Glutamine (Gln) and Vitamin E (VE) supplementation on the performance and immune response of broilers. A completely randomizes experimental design with a 2 x 3 (VE x Gln) factorial arrangement was used. VE was supplemented at 10 and 500 mg/kg feed, with or without Gln (1%) addition, and two periods of supplementation in the starter diets (1-7 and 1-14 days of age), with five replicates of 50 birds each. The analyzed parameters were: live performance (weight gain, feed intake, and feed conversion ratio); relative weights of the spleen, bursa, and thymus; antibody titers (with sheep red blood cells suspension - SRBC) and cutaneous basophilic hypersensivity (CBH). Data were submitted to the analysis of variance, and means were compared using the test of Tukey. Treatments did not influence (P>0.05) live performance parameters or antibody titers. VE reduced (P=0.01) CBH, with the level of 10 mg VE/kg allowing higher cell proliferation as compared to 500 mg VE/kg. As to lymphoid organs, only the spleen was affected (P=0.035) by Gln, which resulted in higher spleen relative weight when fed during the first week of age. Results showed that 10 mg VE/kg with Gln (1-7 days) promoted better immune responses.Studies on carbon-13 turnover in eggs and blood of commercial layers]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400008&lng=pt&nrm=iso&tlng=pt
This paper aimed at evaluating the influence of diets containing different isotopic values of carbon-13 turnover on the half-life of egg (yolk + albumen), yolk and albumen individually, and blood of poultry using delta13C isotopic variation. Commercial layers fed four experimental isocaloric and isonitrogenous diets (RC4, RC3, RMC4 and RMC3) containing different isotopic values, during an experimental period of 56 days. Turnover of the studied tissues was influenced by the experimental diets. Blood and albumen were more influenced by dietary treatments as compared to egg and yolk. The RMC3 diet induced better performance (better feed intake and higher egg production) due faster rate of carbon substitution than the RC4 diet, and lower half-life for egg (yolk + albumen), yolk, and albumen.Development of an enzyme-linked immunosorbent assay for quantification of Salmonella enteritidis-specific antibodies in egg yolk]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400009&lng=pt&nrm=iso&tlng=pt
The present study aims at developing an indirect ELISA to quantify yolk antibodies specific to all surface proteins of the invasive Salmonella Enteritidis (SE), which acquired the 1.8, 14.1, and ~ 50 Kb plasmids. An ELISA checkerboard was used in four different experiments to account for the different parameters included in the preliminary ELISA procedure, and consequently to maximize the difference in Optical Density (OD) values between control positive and negative yolk samples. The first experiment aimed at studying the impact of 5% Bovine Serum Albumin (BSA) dissolved in distilled water as a blocking reagent on a 28 µg/well SE antigen-coated plate, while applying the positive and negative control yolk samples to different concentrations of Phosphate-Buffered Saline (PBS).Conjugate application was maintained constant at a dilution of 1:500 in PBS. The second experiment was similar to the first one, but the positive and negative control yolk samples were diluted in PBS-Tween 20, and the conjugate dilution was changed to 1:1500 in PBS-Tween 20. In the third experiment, the conjugate was diluted at 1:1500 in 5% BSA/PBS-Tween 20 diluent or PBS-Tween 20 diluent with no 5% BSA. The objective of the fourth experiment was to study the impact of four different concentrations of SE-coated antigen levels (28µg/well, 56µg/well, 84µg/well, and 112µg/well), while fixing the blocking step with 5% BSA in distilled water, and the conjugate dilution set at 1:1000 in 5% BSA/PBSTween 20, and fixing the control yolk samples dilution at 1% in PBS-Tween 20. This last experimental procedure allowed the highest difference in mean absorbance OD values of the positive control minus the negative control samples, which was equivalent to 0.381. In addition, the final protocol for this ELISA was applied on individual egg yolk samples of two groups of chicken layers: one challenged in the esophagus at 11 days with 5.4 x 10(10) CFU/ml/bird of SE, and the second group was not challenged. The mean OD values of the egg yolk of antibodies specific against SE of the two groups were significantly different (0.8578 versus 0.5250; p<0.05), which indicates the possible application of the developed ELISA for screening SE infection by examining egg yolks produced by commercial layers.Campylobacter sp in organs and meconium of day-old broiler chicks derived from naturally infected breeder hens]]>http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2006000400010&lng=pt&nrm=iso&tlng=pt
Campylobacter sp is an important agent that causes foodborne infection, particularly in food of poultry origin. Therefore, the efficient control of the transmission routes in chicken farms is of outmost importance to prevent it from spreading. In chicken farms, the main transmission route of this microorganism is horizontal, as the vertical route continues to be the object of inconclusive researches. The objective of this study was to verify the presence of Campylobacter sp in breeder hens, meconium, and other organs of day-old chicks derived from these breeders in order to obtain information on vertical transmission. Microbiological analyses were performed, using cloacal swabs from 279 breeder hens. Positive breeders were segregated, and the presence of Campylobacter sp. was verified in their progeny by analyzing 117 meconium samples; 36 heart, liver and spleen samples (pool of 3 day-old chicks per sample), and 34 intestine samples (pool of 3 chickens in each sample). The analysis of the 279 breeder hens showed that 39 (13.97%) were positive for Campylobacter sp, using the cloacal swab method. The meconium and the organs of day-old chicks were not positive. The physiological characteristics of breeder hens, of eggs, and of Campylobacter sp favor the entrance of bacteria and their survival inside the eggs, and therefore, this probably is the contamination route of day-old chicks. However, chick meconium and organs were negative in the present experiment, indicating that the vertical way of transmission is a rare event.